Electric furnace.



B. REDEH.

. ELECTRIC FURNACE.

APPLICATION FILED JAM- .21.1918.

I lgil. 5; l 2

Patented Nov. 26, 1918.

UNITED STATES mom: manna, or KYKKELSBUD, NEAR ASKIM, NORWAY.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Nov. 26,1918.

Application filed January 22, 1918. Serial No. 213,248.

To all whom it may concern:

' Be it known that I, BJoRN RZEDER, a subject of the King of Norway, residing at Kykkelsrud, near Askim, Norway have invented certain new and useful Improvements in Electric Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying draw-' ings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to electric furnaces and has for its object to provide means whereby the supply of the charge. is easily controlled.

cially in such furnacesin which gaseous reaction products are formed it is of importance that the charge be supplied to the bath in the form of a preheated uniform stream. In several instances it is difiioult to attain this object because at the point where the charge enters into the slag crusts are liable to be formed and thereby obstruct the sinking of the charge.

According to the present invention these difficulties are avoided by the arrangement of supplementary electrodes passing through the bottom of the charge column. These supplementary electrodes or shaft electrodes are suitably inserted through charging and preheating chambers, which are open toward the slag bath. The preheating chambers are preferably arranged in such manner, that the gaseous reaction products formed at the end of the e'lectrode are allowed to escape to the reaction chamber. By the arrangement of such shaft electrodes the place at which the charge enters the bath is always maintained open. The quantity of charge supplied is in this case controlled by means of 0 charging and reaction chambers while maintaining the total tension unchanged. By this latter arrangement changes in the positio.. of the electrodes is obtained and this in many instances may be of great advantage.

The furnace is especially adapted for the reduction of zinc ores.

Along the shaft electrode the zinc vapors are liable ,to force their way upward. This may be counteracted by surrounding a greater length of the electrode by the charge or by means of one or more components of the charge for instance carbon in-the form of powder. For this purpose a jacket of a smaller sectional area than the shaft itself is provided with the result that the charge is brought to form free surfaces at the bottom edge of the acket so that vapors (raw vapor) are allowed to escape.

The invention is diagrammatically illustrated in the accompanying drawing in which Figure 1 is a sectional view of one embodiment of the invention. Fig. 2 illus- In electric slag bath furnaces and espe-' trates a modified furnace construction. In the illustrated examples 1 designates the reaction chamber and 2 the charging shaft or chamber.

The gases from the slag bath 7 in the reaction chamber 1 escape through a channel 9 the spaces 1 and 2 being separated by a wall 10. In Fig. 1 one top electrode 3 is arrangedin the reaction chamber ,1 while another top electrodeis arranged in the charging shaft or chamber 2. These electrodes act to secure an even supply of charge to the slag bath 7' by means of preventing the formation of crusts at the foot of the charge column. The gases formed in the preheating chamber 2 are allowed to escape from the charge surface 6 through a channel 8. The jacket 11 serves to efi'ect-a tightening around the electrode. The supply of current to the two electrodes takes place through a transformer 12 which 'as shown in the drawing is so arranged, that the tension difference between the bottom electrode connected at the. middle and the top electrodes connected at eachend may be controlled as desired without altering the total tension.

' In this manner it is possible to control the supply of charge by means of a greater or lower load on the shaft electrode.

The same result may also be obtained in the usual manner by means of raising or towering the shaft electrode.

The furnace may also be constructed with a greater number of top electrodes.

. A furnace for a two or three phase ourrent could also be constructed with one reaction chamber on each side of the charging shaft as shown in Fig. 2.

I claim: 1. In an electric furnace for the production of zinc and the like, a reaction chamher, an electrode therein, a charging shaft having its walls extending into the reaction chamber and terminating at a point above the level of the bath, and a supplemental electrode in said charging shaft. v

2. In a combincd'electric slag bath and shaft furnace the arrangement of a supplemental. electrode in the charge column in combination with means for changing the tension difference between a bottom electrode and the electrodes in the charge column and in the reaction chamber, and means to maintain the total tension constant during such changes.

3. In an electric furnace for the production of zinc and the like, a reaction chamber, an electrode" therein, a charging shafthaving its Walls extending into-thereaction chamber and terminating at a point above the level of the bath, a supplemental electrode in said charging shaft, and a jacket surrounding the upper portion of the sup-' plemental electrode for the purpose specified.

4. In an electric furnace for the production of zinc and t-hewlike, a charging shaft,

an electrode therein, a. plurality of reaction [chambers arranged around the shaft, the walls of the latter extending into the reaction chambers and terminating at a point BJoRN' RZEDER.

Witnesses: I

C. NORMAN, C. FABRICIUs HANSEN. 

